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排序方式: 共有367条查询结果,搜索用时 31 毫秒
81.
Alfredo Ruiz-Arias Cleotilde Juárez-Ramírez Daniel de los Cobos-Vasconcelos Nora Ruiz-Ordaz Angélica Salmerón-Alcocer Deifilia Ahuatzi-Chacón Juvencio Galíndez-Mayer 《Applied biochemistry and biotechnology》2010,162(6):1689-1707
A microbial community able to aerobically degrade the azo dye Acid Orange 7 was selected from riparian or lacustrine sediments collected at sites receiving textile wastewaters. Three bacterial strains, pertaining to the genera Pseudomonas, Arthrobacter, and Rhizobium, constitute the selected community. The biodegradation of AO7 was carried out in batch-suspended cell culture and in a continuously operated multistage packed-bed BAC reactor. The rapid decolorization observed in batch culture, joined to a delay of about 24 h in COD removal and cell growth, suggests that enzymes involved in biodegradation of the aromatic amines generated after AO7 azo-bond cleavage (1-amino-2-naphthol [1-A2N] and 4-aminobenzenesulfonic acid [4-ABS]), are inducible in this microbial consortium. After this presumptive induction period, the accumulated byproducts, measured through COD, were partially metabolized and transformed in cell mass. At all azo dye loading rates used, complete removal of AO7 and 1-A2N was obtained in the multistage packed-bed BAC reactor (PBR).; however, the overall COD (η COD ) and 4-ABS (η ABS ) removal efficiencies obtained in steady state continuous culture were about 90%. Considering the toxicity of 1-A2N, its complete removal has particular relevance. In the first stages of the packed-bed BAC reactor (Fig. 4a–c), major removal was observed. In the last stage, only a slight removal of COD and 4-ABS was obtained. Comparing to several reported studies, the continuously operated multistage packed-bed BAC reactor showed similar or superior results. In addition, the operation of large-packed-bed BAC reactors could be improved by using several shallow BAC bed stages, because the pressure drop caused by bed compaction of a support material constituted by small and fragile particles can be reduced. 相似文献
82.
M. Carmen Sampedro M. Aranzazu Goicolea Nora Unceta Alicia Sánchez‐Ortega Ramón J. Barrio 《Journal of separation science》2009,32(20):3449-3456
A method based on sequential stir bar sorptive extraction followed by automated thermal desorption–GC–MS for the determination of pesticides in underground and superficial water samples has been developed. Retention time locked GC–MS and deconvolution Automated Mass Spectral Deconvolution and Identification System software allows the use of pesticide databases for identification and quantification in routine applications. Quantitation limits and repetitivity using full scan mass spectrometric determination guarantee the applicability of the method, which enables considerable savings to be made in total analysis time, with data processing times of around 2 min/sample. 相似文献
83.
Lee N 《Journal of AOAC International》2006,89(4):1135-1137
Some food products naturally contain phytoestrogens, but there are few in Western diets that are significant sources. The foods that are the most significant sources are soy beans, containing isoflavones, and flaxseed, which contains lignans. These foods have, however, until recently been relatively little used in Canada and the United States in the human diet. While the Japanese diet contains from 20 to 80 mg of isoflavones per day, Canadian and U.S. diets tend to be below 1 mg/day in the absence of soy protein. The number of foods sold in the West that have ingredients derived from soybeans has been increasing. Many of these have soybean oil, soy protein, or other ingredients serving functional roles in the food. However, with increasing interest among consumers in dietary choices that help to improve health and reduce risk of disease, products in which soy is featured are quite readily available, and it is common, at least in Canada, to find bread and other bakery products with flaxseed added. Soy foods sales in the United States increased at a 15% compounded annually growth rate between 1992 and 2003, with a major increase occurring between 2000 and 2001 (1). Growth rates are reported to have declined somewhat in 2004 (2). The U.S. Food and Drug Administration approval of a health claim associating soy protein intake with reduced risk of heart disease in 1999 is attributed with fueling the very sizable growth since 2000. The claim identifies 25 g/day as the amount needed to derive the claimed health benefit. Because the isoflavone content of soy products is highly variable, depending on the method of processing (3), it is difficult to estimate quantitatively the impact of the increased rate of soy product consumption on soy isoflavone intake, although an overall increase can be expected. In contrast, 相似文献
84.
Jouyban A Chan HK Chew NY Khoubnasabjafari M Acree WE 《Chemical & pharmaceutical bulletin》2006,54(4):428-431
The Jouyban-Acree model has been used to predict the solubility of paracetamol in water-ethanol-propylene glycol binary and ternary mixtures based on model constants computed using a minimum number of solubility data of the solute in water-ethanol, water-propylene glycol and ethanol-propylene glycol binary mixtures. Three data points from each binary solvent system and solubilities in neat solvents were used to calculate the binary interaction parameters of the model. Then the solubility at other binary solvent compositions as well as in a number of ternary solvents were predicted, and the mean percentage deviation (+/-S.D.) of predicted values from experimental solubilities was 7.4(+/-6.1)%. 相似文献
85.
OBJECTIVE: To examine the role of the practitioner, informed consent, and genetic counseling in genetic testing decisions and to assess their relative influence on women's decision to have clinical BRCA1/2 testing. METHODS: Qualitative study using in-depth open-ended interviews with 68 women who had considered clinical BRCA1/2 testing. RESULTS: Slightly less than half of the women who had considered BRCA1/2 testing were found to have had a clear and preexisting desire to test or not to test, irrespective of practitioner attitude or advice. CONCLUSION: The decision to accept or decline genetic testing is the result of a complex process that goes beyond interactions between health care providers and patients, indicating a caution against exclusive reliance on informed consent or counseling encounters. 相似文献
86.
87.
Cagri Üzüm Nora Kristen Regine von Klitzing 《Current Opinion in Colloid & Interface Science》2010,15(5):303-314
The review addresses the influence of polyelectrolytes on the statics and dynamics of thin liquid films. Both, changes of interfacial and bulk properties, contribute to the overall behaviour of thin films formed from aqueous polyelectrolyte solutions. Therefore, the chapter is separated into two parts: polyelectrolytes at film interfaces and polymers in film bulk. 相似文献
88.
89.
Nora C. Hopkins Michael K. Kinyon 《Transactions of the American Mathematical Society》1999,351(11):4545-4559
Quadratic differential equations whose associated algebra has an automorphism of order two are studied. Under hypotheses that naturally generalize the cases where the even or odd part of the algebra is one dimensional, the following are examined: structure theory of the associated algebra (ideal structure, simplicity, solvability, and nilpotence), derivations and first integrals, trajectories given by derivations, and Floquet decompositions.
90.
Nora Graf Eda Yegen Thomas Gross Andreas Lippitz Wilfried Weigel Simone Krakert Andreas Terfort Wolfgang E.S. Unger 《Surface science》2009,603(18):2849-2860
The chemical constitution of functionalized supports is an important parameter that determines their performance in a broad range of applications, e.g. for immobilization of biomolecules. Supports with amino functionalized surfaces are also often used for DNA microarray experiments. However, spectral data which have been reported for surfaces with amino functionalities suffer from some inconsistencies. In this article a detailed XPS (X-ray photoelectron spectroscopy) and NEXAFS (Near edge X-ray absorption fine structure) database for amino functionalized surfaces is presented. Amino-terminated surfaces prepared from aliphatic and aromatic aminosilanes or aminothiols and a field sample are considered. Effects of aging in air and damage by radiation are addressed as well. 相似文献